The principal achievements of Mansa Musa were in three main areas: the expansion of the Mali Empire by conquest, an extensive building program, particularly in Timbuktu, and various contributions to scholarship, including his development of a major university and one of the largest libraries in the medieval world.
Mansa Musa significantly extended the territory of Mali. He conquered twenty-four cities and their surrounding districts and recaptured several areas that had formerly been part of the Mali Empire but were lost by previous generations, including the important trading center of Gao. He built palaces, mosques, and madrasas in Gao and Timbuktu, bringing architects from Andalusia and Egypt to design them. One of his greatest contributions to architecture is the Djinguereber Mosque in Timbuktu.
Also in Timbuktu is the University of Sankore, which was founded in the tenth century but greatly enlarged, renovated, and restaffed by Musa. The university library had a collection of 1,000,000 manuscripts, the largest library in Africa since the Great Lirary of Alexandria. Mansa Musa made Timbuktu one of the principal centers of learning in Africa for centuries.
These achievements, however, do not quite capture the full historical importance of Mansa Musa. He is one of those figures from history around whom legends have grown. His pilgrimage to Mecca, for instance, was conducted on such a grand scale that the money he spent on the way is said to have lowered the price of gold in North Africa for the next century. Mali may well have produced more gold than anywhere else in the world during Musa's reign and, though such comparisons ultimately mean very little, he has a plausible claim to have been the richest man who ever lived. His piety as a Muslim was also legendary, and he played a large part in making the Mali Empire a center of Islamic scholarship.